Google adds feature to explain why certain ads pop up

Reporting from San Francisco — A lot of people still don't understand why certain advertisers target them while they are searching the Web.

Google is rolling out a new feature that explains why its users see certain ads when they search Google or check their Gmail.

The move comes as Google, like other Internet companies, finds itself in the cross hairs of lawmakers and regulators as they scrutinize how consumers' personal information is collected and used online. Google says it tries to be transparent about the information it collects and show consumers the most relevant ads.

"Our advertising system is designed to show the right ad to the right person at the right time. Because ads should be just as useful as any other information on the Web, we try to make them as relevant as possible for you," Susan Wojcicki, Google's senior vice president of advertising, wrote in a blog post.

Wojcicki said the new feature, called "Why these ads," helps users learn why they see certain ads and gives them the ability to block advertisers or opt out of ads that are personalized to them.

For example, Google search users who click on "Why these ads?" next to ads that show up in search results will get an explanation such as "this ad is based on your current search terms." Users can then decide if they want to block that advertiser or turn off ad personalization altogether.

Users of Gmail, Google's email service, will also be able to block advertisers. Google serves up ads based on the contents of emails (although Google says it does not "read" your emails).

Google derives the vast majority of its revenue from advertising, chiefly search ads, which are popular because businesses can track the effectiveness of their ad dollars.

What Google still does not do: let users stop Google from collecting information based on their search history.

Privacy watchdogs remain skeptical.

"For every little tool Google provides to help users protect their data, they create a host of new digital marketing apps to capture it," said Jeffrey Chester, executive director of the Center for Digital Democracy. "The test of this new tool will be to see if it really enables you to control your information."